1. Field of the Invention
The present invention relates to an electrostatic discharge protection apparatus, and more particularly, to an electrostatic discharge protection apparatus which utilizes a parasitic silicon controlled rectifier (SCR) for electrostatic protection.
2. Description of Related Art
With the advancement in semiconductor fabrication process, the gate oxides of transistors in nowadays semiconductor fabrication process are becoming increasingly thinner and, as a result, can be more easily damaged in an electrostatic discharge (ESD) event. Therefore, it is desired to develop an ESD protection technique for the current semiconductor fabrication.
Existing ESD protection apparatus are often constructed by ESD protection elements that have thin gate oxides. The ESD protection elements having thin gate oxides produce a large leakage current during a normal operation of the circuit which the ESD protection elements belong to. On the contrary, the ESD protection apparatus is constructed by the ESD protection elements having thick gate oxides, it is hard to trigger the ESD protection apparatus can be hard, and such as that the protection effect is reduced.
In addition, silicon controlled rectifiers (SCRs) are conventionally used to construct the ESD protection apparatus. However, the conventional SCRs are hard to trigger (which requires a high triggering voltage). As a result, damage to elements (having thin gate oxides) of the circuit which the SCR belongs to often occurs before the SCR is triggered, thus making it unable to achieve the ESD protection function.